Sometimes things go easy .... sometimes you have to dig deeper to find the root cause
I agree that an ICP analysis s the next logical step.
It will proof right or wrong wether you have an issue with a certain "killer parameter" like heavy metals poisoning your water.
Here is some more food for thougts in finding the root cause
A) Light and Flow !
SPS can be Diva's in this respects.
- UV Light is required for photosynthesis. It is much better if this is "coming from all around" to the SPS and with the "correct intensity AND UV specturm" (strong but not too strong, spectrum ok). All the Super-SPS stuffed tanks i have seen over several years in Germany used T5-lightnings. Some of them combined with LED or HQIs, but always full T5 coverage over the whole length/depth of the tank. A look on this visualization explains why this is the case.
.... i know chaning of lightning is costly... but maybe it is the way you have to go. Do you have an option to lend/try out a T5 Panel ??
Also flow especially around the SPS branches Polyps is important. Corals polyps can fetch food only if it circulates around them.
B) "Too many" of some traces ?
I did not use Triton method on my own. For me it is a bit suspect and i perceive it as kind of "over-engineering". The risk is to overdose certain traces, eg Potassium which can be counter productive/harmfull if level are too high.
Dosing traces "together" with the dosing you do anyhow for Ca and Alk, with the same matched consumption rate of your tank is preferred from my side
c) Corals suffering ?
There is a situation between healthy/colorful and RTN for SPS.
In case your nutrients are not "close to" but really "0" a check with feeding with amino acids can be worth a try
i really hope that you manage to find out and elimnate the cuase especially as you seem to do a lot of things right obviously already and show the required energy level you need to have as a really successful reefer
kind rgds
Martin
